1. Field
One or more embodiments of the present disclosure relate to a camera assembly to acquire an image having a wide viewing angle.
2. Description of the Related Art
A method of physically arranging a plurality of cameras may be used to acquire an image having a wide viewing angle. This method may require a large space and registration of acquired images. In this method, however, configuration may be easy and image distortion may be low.
Alternatively, a wide-angle lens may be used to acquire an image having a wide viewing angle. That is, a wide-angle lens or a fisheye lens may be used to acquire a wide viewing angle. Such a lens generally has a focal distance less than about 50 mm, which is a focal length used in a camera for most general-purpose photography. Thus, the wide-angle lens has a wider viewing angle than a standard lens. For example, ae wide-angle lens typically has a viewing angle of about 120 degrees. A fisheye lens typically has a viewing angle of about 180 degrees, which is greater than that of the wide-angle lens. An image acquired by the fisheye lens, however, may be distorted.
It may be necessary for a camera to satisfy several conditions such that the camera is used in an endoscope, such as a laparoscope used in a small area like the abdominal cavity during surgical operation. First, it may be necessary for the size of the camera to be small. The camera may be inserted into an orifice of the human body or through an incision during a surgical operation. When the size of the camera is large, the incision must be enlarged or a space desired for the surgical operation may be reduced. For this reason, one camera or a minimum number of cameras may be used instead of an arrangement of a plurality of cameras. Second, it may be necessary for the camera to have a wide viewing angle. The camera may monitor motion of surgical tools near the camera and an environment of a surgical region in addition to observing the front of the surgical region. A front visual field may be provided through a high-quality image without distortion as if a human were directly viewing an object with the naked eye.
Consequently, it may be necessary to develop a camera having a small size and a wide viewing angle which is suited to a laparoscope or a surgical robot.